WORLD INTELLECTUAL PROPERTY 0RGA>a2ATION
International Bureau
PCX
INTERNATIONAL APPLICATION PUBUSHED UNDER THE PATENT COOPERATION TREATY (PCT)
(51) International Patent Classification :
G02F 1/1335
Al
(11) International Publication Number:
(43) International Publication Date:
WO 00/41030
13 July 2000 (13,07.00)
(21) IntemaUonal Application Number: PCr/US99/27720
(22) IntemaUonal Filing Date: 22 November 1999 (22.1 1.99)
(30) Priority Data:
09/224^91
31 December 1998 (31.12.98) US
(71) Applicant: HONEYWELL INC. lUS/US]; Honeywell Plaza.
Minneapolis, MN 55408 (US).
(72) Inventors: LARSON. Brent, D.; 4713 E. Cascalote Drive, Cave
Creek. AZ 85331 (US). HAIM, Elias. S.; 18863 N. 69th
Avenue, Glendale, AZ 85308 (US).
(74) Agent: ANDERSON, William, C; Honeywell Inc., Honeywell
Plaza - MN12^251. P.O. Box 524, Minneapolis. MN
55440-0524 (US).
(81) Designated States: JP, European patent (AT, BE. CH. C Y. DE.
DK, ES. PI, FR, GB, GR, IE. IT, LU, MC, NL, PT. SE).
Published
With intematlohai search report.
Before the ejq>iration of the time limit for amending the
claims and to be republished in the event of the receipt of
amendments.
(54)TiUe: REDUCED REFLECTANCE POLARIZED DISPLAY
(57) Abstract
A method and apparatus according to various aspects of the present Invention provides a polarized display exhibiting reduced
reflectances. A polarizer is disposed adjacent to a cover glass in front of the display. Light intended to be transmitted by the display is
transmitted by die polarizer. Light reflected after passing through the polarizer reverses polarization, and is absorbed as it intercepts the
polarizer following reflection.
I
FOR THE PURPOSES OF INFORMATION ONLY
Codes used to identify States party to the PCX on the front pages of pamphlets publishing international applications under the PCX.
AL
Albania
ES
Spain
LS
Lesotho
SI
Slovenia
AM
Annenia
n
Finland
LT
Lithuania
SK
Slovakia
AT
Austria
FR
France
LU
Luxembourg
SN
Senegal
AU
Australia
OA
Gabon
LV
Latvia
sz
Swazihmd
AZ
Azertwijan
GB
United Kingdom
MC
Monaco
TD
Chad
BA
Bosnia and Herzegovioa
G£
Oeoigia
MD
Republic of Moldova
TG
Togo
BB
Baibados
GH
Ghana
MG
Madagascar
TJ
Tajikistan
BE
Belghun
GN
Guinea
MK
The former Yugoslav
TM
TUricmenistan
BF
. BuzkinaPaso
GR
Greece
Republic of Macedonia
TR
Turkey
BG
Bulgaria
HU
Hungary
ML
Mali
TT
Trinidad and Tobago
BJ
^ Benin
IE
Irclaml
MN
Mongolia
UA
Ukraine
BR
Brazil
IL
Israel
MR
Mauritania
UG
Uganda
BY
Belanis
IS
Iceland
MW
Malawi
US
United States of America
CA
Canada
IT
Italy
MX
Mexico
uz
Uzbekistan
CF
Central African Republic
JP
Japan
NB
Niger
VN
Viet Nam
CG
Congo •
KE
Kenya
HL
Netherlands
YU
Yugoslavia
CH
Switzerland
KG
Kyisyzstan
NO
Norway
zw
2^babwe
a
Cdte d'lvoire
KP
Democratic People*! ,
NZ
New Zealand
CM
Cameroon
Republic of Korea
PL
Poland
CN
China
KR
R^mblic of Korea
FT
Portagal
CI)
Cuba
KZ
Kazakstan
RO
Jtomania
C2
Czech Republic
LC
Saint Luda
RU
Russian Federation
DS
Gerniany
U
Liechtenstein
SD
Sudan
DK
Denmack
LK
SH Lanka
5E
Sweden
EE
Estonia
LR
Uberia
SG
Singapore
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PCTAJS99/27720
REDUCED REFLECTANCE POLARIZED DISPLAY
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to displays, and more particularly, to methods and
apparatus for reducing unwanted reflections in displays.
DESCRIPTION OF THE RELATED ART
In display applications, it is difficult to maintain high contrast output at
high ambient illumination levels. However, polarized light displays and active
matrix liquid crystal display (AMLCD) flat panels work well in maintaining the
contrast in their displays because light passes through several absorbing layers
before reflecting or scattering back out from the light producing mechanism. The
multiple layers, however, adversely affect the total reflectance of the display.
Even though the reflectance at layer boimdary in itself may be quite small, the
sum of the reflections may be significant.
Referring to Figure 1, a conventional polarized display 2, such as a liquid
crystal display (LCD), includes a cover glass 4 having an antireflective coating 6.
A front polarizer 8, a first substrate 10, a Uquid crystal layer 12, a second substrate
14, and a rear polarizer 16 are sandwiched between the cover glass 4 and a
backlight 18. The cover glass 4 is separated from the front polarizer 8 by a gap 9,
typically filled with air. The reflectance at each boundary between the layers adds
to the overall reflectance of the display. Reflectances associated with the
boundaries between the cover glass 4, the gap 9, and the front polarizer 8 are
especially prono\mced.
Several methods have been developed to reduce reflectances. For
example, antireflection coatings 6 may be added to one or both sides of the cover
glass 4, which tends to reduce the reflection from the fix)nt of the cover glass 4.
Additionally, an antireflection coating may be added to the surface of the front
polarizer 8. However, the suppression of the residual reflection still remains a
problem. Another method involves applying adhesives between the cover glass 4
and the front polarizer 8 to bond the glass to the polarizer and achieve some level
of index matching, which tends to reduce the reflectances from the boundary
between the cover glass 4 and the air gap 9 or the front polarizer 8. While
bonding the cover glass 4 to the display is somewhat successfiil in reducing
0
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reflectances, it tends to affect the uniformity of the liquid crystal cell gap, induces
difficulty in repairs, and is associated with other problems due to aging effects and
shrinkage of the adhesive.
Another alternative is to add attenuating contrast enhancement filters to
5 the display to filter out the reflectances. For example, a filter may be added
between the cover glass 4 and the gap 9 or the front polarizer 8, or alternatively a
specialized tinted glass may be used for the cover glass 4. Addition of the filter
reduces reflection, but also attenuates the display output. Further, addition of the
filter tends to promote other issues, such as cost, color shifts, and environmental
10 concerns.
SUMMARY OF THE INVENTION
A display according to various aspects of the present invention comprises
a polarized display that has reduced reflectances in the output of the display to
15 maintain high contrast output, high illumination levels, and less expensive
production. A polarizer is disposed adjacent to a cover glass in firont of the
display. Light intended to be transmitted through the display is transmitted by the
polarizer. Light reflected after passing through the polarizer is further attenuated
as it intercepts the polarizer following reflection.
20
BRIEF DESCRIPTION OF THE DRAWING FIGURES
The subject matter of the invention is particularly pointed out and
distinctly claimed in the concluding portion of the specification. The invention,
however, both as to organization and method of operation, may best be
25 understood by reference to the following description taken in conjimction with the
claims and the accompanying drawing, in which like parts may be referred to by
^ ' like numerals:
Fig. 1 shows a conventional polarized display.
Fig. 2 shows a polarized display according to various aspects of the
30 present invention.
Fig. 3 shows an alternate embodiment of a polarized display according to
various aspects of the present invention.
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"3-
DETAILED DESCRIPTION OF PREFERRED
EXEMPLARY EMBODIMENTS
The subject matter of the present invention is particularly suited for use in
connection with displays, such as LCDs. As a result, the preferred exemplary
5 embodiment of the present invention is described in that context. It should be
recognized, however, that such description is not intended as a limitation on the
use or applicability of the present invention, but is instead provided merely to
enable a fiill and complete description of a preferred embodiment.
Referring now to Figure 2, a display 2 according to various aspects of the
10 present invention comprises: a cover glass 4; a front gap 9; a front polarizer 8; a
first substrate 10; a liquid crystal layer 12; a second substrate 14; a rear polarizer
16; an auxiliary polarizer 20; and a backlight 18. Each of the components of the
display 2 is suitably a conventional LCD component. In particular, the cover
glass 4 suitably comprises a conventional cover glass for use in conjunction with
15 LCDs, especially high contrast LCDs, to protect the underlying components and
transmit light from the backlight passing through the other components. While
referred to as a cover glass, the cover glass 4 can be made from glass, plastic or
any other fully or partially transparent material with suitable physical properties.
To reduce reflections at the boundary between the cover glass 4 and the front gap
20 9, the rear surface of cover glass 4 adjacent the front gap boundary 9 or auxiliary
polarizer 20 may include a suitable antireflection material. For example, the rear
surface of the cover glass 4 may include an antireflection coating, film, sheet, or
any other form of antireflection material. The addition of the antireflection
coating to the rear of the cover glass 4 tends to reduce reflections at the boundary
25 between the cover glass 4 and the auxiliary polarizer 20 or, if the auxiliary
polarizer 20 is omitted, the front gap 9.
The front and rear polarizers 8, 16 suitably comprise conventional
polarizers for use in conjunction with LCDs. The front and rear polarizers 8, 16
. may be oriented in any suitable manner to selectively transmit light from the
30 backlight 18 to the viewer through the front and rear polarizers 8, 16 and the
liquid crystal layer 12.
Similarly, the first and second substrates 10, 14 suitably comprise
conventional LCD transparent substrates. The substrates 10, 14 suitably comprise
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PCTAJS99/27720
sheets of transparent material, such as glass coated with indium tin oxide or
otherwise suitably coated glass or transparent polymer.
A space is formed between the substrates 10, 14 and filled with the liquid
crystal layer 12. The liquid crystal layer 12 may comprise any suitable liquid
crystal material, such as a twisted nematic or supertwisted nematic material. A
seal formed around the edges of the substrates 10, 14 inhibits leakage of the liquid
crystal material 12 from between the substrates 10, 14. The display may comprise
a monochrome gray-scale display, a binary display, a color display, or any other
type of display. Similarly, the backlight 18 comprises any appropriate light
source for illuminating display 2. In some embodiments, the backlight 18 may be
omitted and the display 2 reconfigured as a reflective display.
In the present embodiment, the display includes the auxiliary polarizer 20
between the front gap 9 and the cover glass 4. The front gap 9 separates the
auxiliary polarizer 20 from the front polarizer 8. The auxiliary polarizer 20 may
be bonded to the .cover glass 4 or otherwise retained in display 2, and may be
coated with an antireflective coating on one or both surfaces. The auxiliary •
polarizer 20 is an absorbing polarizer, preferably of a similar type as the front
polarizer, and is preferably aligned in the same direction as the front polarizer 8,
Alignment of the polarizers 8, 20 in the same direction minimizes the attenuation
of light coming from the backlight 18. This allows maximum transmission of the
light with little to no attenuation of the light. Reflected light, however, initially
passes through the cover glass and is polarized by the auxiliary polarizer 20. By
removing one of the polarizations before it reaches the gap 9, the reflections from
each of tiie interfaces between the auxiliary polarizer 20 and front polarizer 8 are
reduced by around 50%. This allows for reduced overall reflections, or can be
used to reduce the reflectance requirements for any antireflection coatings which
may be appUed to the front and auxiliary polarizers 8, 20.
Whereas the incorporation of auxiliary polarizer 20 affects the reflectances
in the vicinity of the gap 9 most directly, the configuration can also be adjusted in
a manner which provides very convenient and beneficial introduction of
attenuation for other reflectances. By selecting an auxiliary polarizer 20 with
somewhat lower transmittance, the functionality of a conventional attenuating
contrast enhancement filter can be achieved without additional elements or cost.
Alternately, similar attenuation can be achieved by rotating the polarizing axis of
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auxiliary polarizer 20 relative to the polarizing axis of front polarizer 8. In both
cases, a significant degree of contrast enhancement can be achieved with a
minimum of additional cost, complexity or risk of chromatic variation in the
display output.
5 In an alternative embodiment, the auxiliary polarizer 20 is included in the
display 2, and the front polarizer 8 is omitted. Operationally, the display 2
functions identically; light transmitted through the liqmd crystal layer 12 is either
polarized in the direction of the rear polarizer 16 (i.e., substantially imafifected by
the liquid crystal layer 12), or is polarized in another direction by the liquid crystal
10 layer 12. Whether the light is transn:iitted to the viewer depends on the orientation
of the front polarizer 8 or, in the present embodiment, the auxiliary polarizer 20.
In the absence of the front polarizer 8, light which is not polarized in alignment
with the auxiliary polarizer 20 is absorbed and not transmitted to the user.
Another embodiment of the present invention includes an index matching
15 material disposed in the front gap 9. The index matching material may comprise
any suitable material for more closely matching the refractive index of the
materials adjacent the front gap 9, such as the cover glass 4, auxiliary polarizer 20,
or the antireflection material on the rear of cover glass 4, and the front polarizer 8
or the antireflection material on the front surface of the front polarizer 8. The
20 index matching material may comprise any material having an appropriate
refractive index, may be in any suitable form, such as gel, epoxy, oil, liquid,
plastic, gas, or the like. In addition, the index matching material may also have an
appropriate antireflective material, such as a coating, plating, or fihn, to further
reduce reflections.
25 The front polarizer 8, the rear polarizer 16, and/or the auxihary polarizer
20 may also include antireflection material to reduce reflectance. For example,
any or all of the polarizers may be coated, plated, or otherwise integrated with or
adjacent to an antireflection material. In one embodiment, the antireflection
. material is integrated into the polarizer, such as with commercially available
30 antireflection-coated polarizers available from Nitto or other polarizer supphers.
In addition, any or all of the polarizers 8, 16, 20, particularly auxiUary polarizer
20, may be lower efBciency polarizers which transmit only a fraction of the light
polarized in the direction of polarization. For example, a polarizer which
transmits 85% of the light polarized in the direction of polarization transmits 85%
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PCTAJS99/27720
of the light from the backlight to be transmitted. The polarized portion of the light
reflected through the cover glass 4, however, is attenuated as it passes through the
polarizer both ways. Therefore, the overall reflectance of the polarized portion is
reduced by 27.75%. This configuration may be appropriate for various
5 applications requiring low reflectance and adaptable to less than optimal overall
brightness.
Referring to Figure 3, another display according to various aspects of the
present invention employs circular polarization to reduce reflectances in the
vicinity of the gap 9. A linear auxiliary polarizer 20 is disposed adjacent to the
10 cover glass 4. A retarder, such as a quarter wave retarder 22a, is disposed
adjacent to the linear auxiliary polarizer 20, such that light passing through the
auxiliary polarizer 20 and the wave retarder 22a is substantially circularly
polarized. Similarly, a second quarter wave retarder 22b is disposed adjacent to
the front polarizer 8 to achieve substantially circular polarization for light which
15 passes through the display from the other side. The retarder axes are arranged at a
suitable angle from the polarizer axes, such as 45 degrees, to achieve substantially
circular polarization in the gap 9 for light incident from either the front or back of
the display. The auxiliary polarizer 20 and the retarders 22a-b are oriented to
achieve the same substantially circidar orientation, or "handedness'* (i.e., left-
20 handed or right-handed), so that light transmission from the backlight 18 is not
affected. For example, light passing through the front polarizer 8 and the first
wave retarder 22a is circularly polarized in a first direction. Because the auxiliary
polarizer 20 and the second wave retarder 22b transmit light having the same
circular polarization as the front polarizer 8 and the first wave retarder 22a, light
25 from the backlight 1 8 tends to be transmitted.
Reflected light, however, is absorbed by the polarizers. Light initially
' transmitted through the auxiliary polarizer 20 and the first retarder 22a is
circularly polarized in a first direction. Light reflected firom a boundary, however,
reverses the direction of its circular polarization. Thus, as the reflected light from
30 the interface between the gap 9 and the retarder 22a, or the gap 9 and the retarder
22b, intercepts the auxiliary polarizer 20 and the retarder 22a, the light is
absorbed.
While the present circular polarization method is effective at eliminating
the reflectance associated with the gap 9 and its surrounding layers, even further
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PCTAJS99/27720
reduction is possible by suitably associating each of the retarders 22a-b with at
least one antireflection layer, for example between the retarders 22a-b and their
respective polarizers 8, 20 or the gap 9 to reduce reflections at the corresponding
boundary.
In one embodiment of the present display, the quarter wave retarders 22a
and 22b are identical but are oriented with their respective optical axes offset by
90 degrees from each other. In this case, the front polarizer 8 and the auxiliary
polarizer 20 are preferably oriented with parallel polarization axes. This
configuration uses common components and tends to provide both minimum
reflection and maximum transmission for light which is distributed over a
moderate range of angles relative to the display normal. At very steep, or wide
angles, performance can be degraded slightly, however, both in terms of
reflection or especially transmission. Alternative configurations may provide
optimization for displays requiring Avide angle performance.
In an altemative embodiment of the present display configured for wide
angle operation, the quarter wave retarders 22a, 22b have opposing birefiingence
to improve the transmissibility of the display at large viewing angles. One quarter
wave retarder has positive birefringence (n^ > nj and the other quarter wave
retarder has negative birefiingence (n^ < n^,). The optical axes of the quarter wave
retarders are aligned parallel to one another and 45 degrees from the polarization
axis. In this configuration, the phase shifts through the retarders 22a and 22b
cancel each other out over a wide angular range.
Additional circular polarizer configurations can be designed which
incorporate multiple layer retarders and irregular materials or angles. These might
be used, for example, to implement wide-band quarter wave retarders, to achieve
achromatic perforaiance, to shift the angle at which maximum reflectance
reduction is obtained, or even to achieve chromatic performance which varies with
angle of the transmitted light.
While the principles of the invention have now been made clear in
illustrative embodiments, there will be immediately obvious to those skilled in the
art many modifications of structure, arrangements, proportions, the elements,
materials and components, used in the practice of the invention which are
particularly adapted for a specific environment and operating requirements
without departing from those principles.
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PCT/US99/27720
CLAIMS
1. A reduced reflectance polarized display for use with a light source,
comprising:
a display apparatus located a small distance in front of the light soiirce;
a cover glass, having a front side and a back side, located a small distance
in front of the display apparatus with the back side facing the display apparatus;
and
an auxiliary polarizer attached to the back side of the cover glass facing
the display apparatus to reduce reflections wherein only apparatus existing
between the display apparatus and the cover glass is the auxiliary polarizer.
2. The display of claim 1 wherein the auxiUary polarizer is coated
vdth an antireflection coating facing the display apparatus to further reduce
reflections.
3. The display of claim 1 wherein the display apparatus has a front
side and a back side, further comprising:
a first substrate attached to the front side of the display apparatus and a
second substrate attached to the back side of the display apparatus;
a front polarizer, having an antireflection coating, attached to the first
substrate facing the auxiliary polarizer; and
a rear polarizer attached to the second substrate facing the hght source.
4. The display of claim 1, further comprising a first quarter wave
retarder attached to the auxiliary polarizer and a second quarter wave retarder
attached to the display apparatus facing the auxiliary polarizer.
5. The display of claim 3, further comprising a first quarter wave
retarder attached to the auxiliary polarizer and a second quarter wave retarder
attached to the front polarizer, ...
6. The display of claim 3 wherein the auxiliary polarizer and the front
polarizer are aligned in the same direction.
wo 00/41030
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PCT/US99/27720
7. The display of claim 3 wherein the auxiliary polarizer and the front
polarizer have parallel polarization axes.
8. The display of claim 5 further comprising antireflection coatings
on the first quarter wave retarder and the second quarter wave retarder,
9. The display of claim 5 wherein the first quarter wave retarder and
the second quarter wave retarder have opposing birefringence.
10. The display of claim 5 wherein the first quarter wave retarder and
the second quarter wave retarder are wideband quarter wave retarders.
11. A reduced reflectance polarized display for use with a backlight,
comprising:
a display layer placed between a front substrate and a rear substrate, both
having a first and second surface wherein a rear polarizer is attached to the second
surface of the rear substrate, located closer to the backlight, and a front polarizer is
attached to the first surface of the fix)nt substrate wherein the front polarizer is
coated with an antireflection coating; and
a cover glass having a first side and a second side with an antireflection
coating coated on the first side; and
an auxiliary polarizer attached to the second side of the cover glass
wherein the auxiliary polarizer, located a small distance from the front polarizer,
is facing the front polarizer to reduce reflections in the display wherein only
apparatus existing between the front polarizer and the cover glass is the auxiliary
polarizer.
12. The display of claim 11 wherein. the auxiliary polarizer is coated
with an antireflection coating facing the front polarizer to fiirther reduce
reflections in the display.
wo 00/41030 PCT/US99/27720
-10.
13. The display of claim 11, further comprising a first quarter wave
retarder attached to the auxiliary polarizer and a second quarter wave retarder
attached to the front polarizer.
14. The display of claim 1 1 wherein the auxiliary polarizer and the
front polarizer are aligned in the same direction,
15. The display of claim 11 wherein the auxiliary polarizer and the
front polarizer have parallel polarization axes.
16. The display of claim; 13 further comprising antireflection coatings
on the first quarter wave retarder and the second quarter wave retarder.
17. The display of claim 13 wherein the first quarter wave retarder and
the second quarter wave retarder have opposing birefiingence.
1 8. The display of claim 13 wherein the first quarter wave retarder and
the second quarter wave retarder are wideband quarter wave retarders.
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PCTAJS99/27720
INTERNATIONAL SEARCH REPORT
Inti Jonal Appftcatlon No
PCT/US 99/27720
A. CLASSIFICATION OFSUBJECT MATTER
IPC 7 G02F1/1335
Aooordng to tntemattonal Patent ClaasHleatlon (IPC) or to both national daasiflcatlon and IPC
a FIELDS SEARCHED
Minimum documantstlon ooarched (daasfflcaflon system followed by claasHleatlon aymbole)
IPC 7 G02F G02B
Documentation aearched other than minimum documentation to the extent that such documents are included in the fields searched
Etoctronlo data base consulted durino the Intsmatlonal search (name of data baae and, where practical, eearch terms used)
a DOCUMENTS CONSIDERED TO BE RELEVANT
OateQMy*
Citation of document, with Indication, where appropriate, of the relevant
Relevant to dalm No.
PATENT ABSTRACTS OF JAPAN
vol. 1996, no. 03,
29 March 1996 (1996-03-29)
& JP 07 301795 A (SHIMADZU CORP),
14 November 1995 (1995-11-14)
abstract
-& JP 07 301795 A
figures 1,4,8
US 5 486 840 A (ALLISON CHARLES R ET AL)
23 January 1996 (1996-01-23)
column 1, line 65 -column 2, line 55
column 3, line 32 -column 4, line 49;
figures 4,5
1-3,11,
12
4-10,
13-18
4-11,
13-18
-/-
m
Further documenta are Bsted In the oonHnuation of box C.
ly [ Patent family maint>ere ars listed In annex.
* Special oategoilee of otted documents:
*A' document defining the general stats of the art which b not
oortalderad to be of partloular relevance
"E* earfiar document but putiQtfted on or aftM* the International
. flUngdate
V document which may throw double on priority claim(a) or
' which Is dted to eetablish the publication data of another
citatian or other special reason (as speeded)
"O* document referring to an oral diacloeure, use, exhibition or
other means
"P" document pubBshed prior to the International fDIng date but
later ttian the prtortty date datmed
T lalsr document publfehed after the International filing date
or prtortty date and not In. oonfBct with the applioatlon but
dted to urtderstarxl the prtndpb or theory uitdsrtylng the
Invention
*X" document of particular ralevanoe; the claimed Invention
cannot be conaldered novel or cannot be oonstdered to
Involve an inventive step when the document Is talcenalone
"Y' document of paiticutarretevanoe: the claimed Invention
cannot be considered to invdve en biventlve stepwhenthe
document Is combined with one or more other such docu-
ments, such oomtiinatlon bting obvious to a person eklBed
Intheart
document member of the same patent family
Date of the actual oompletiQn of the Intemotbnal asarch
9 May 2000
Date of mailing of the International search report
- 18/05/2000
Name and maUtng addraes of the ISA
European Patent Office, ?JB* 6818 Patsntiaan 2
NL-.2280HVR1JSWIPC
Tel. (431-70) 340-2040, Tx, 31 651 epo nl.
Fax: (+31-70) 340-3016
Authorized officer
Nanntz, U
Fbim PCT/ISAOIO (Moond ahott) (July 1992)
page 1 of 2
1
INTERNATIONAL SEARCH REPORT
Intt. .donal Appaeatlon No
PCT/US 99/27720
CXComtnuitlon) DCX:UMENTS CONSIDERED TO BE RELEVANT
Category*
CttaUon of document with lndIcaliOT,when9 appropriate, of the relevant pfl««»**gft^
Relevant to daim No.
A
us 5 701 165 A (KUBO MASUMI ET AL)
23 December 1997 (1997-12-23)
columh 13, line 44 -column 15, line 35;
figure 12
1-18
Forni PCT/ISASIO (omttnuotlen of aaeond thott) (JuV 1002)
page 2 of 2
INTERNATIONAL SEARCH REPORT
tnfonnatlan on patent (amity memberB
Intft. .donfti Apptloatlon No
pcT/us ^^imi^
Patent document
cited In search report
Publication
Patent family
m6mber(8)
Publication
JP 07301795
A
14-11-1995
NONE
US 5486840
A
23-01-1996
NONE
US 5701165
A
23-12-1997
OP
8076081 A
22-03-1996
DE
19520626 A
11-01-1996
KR
185455 B
01-05-1999
Fom PCT/ISAAl 0 (patent f«nOy miMac) guly 1862)
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